DC Motor Speed Controller Without Microcontrollers

This setup demonstrates how to control the speed of a DC motor using basic electronic components instead of microcontrollers. The circuit relies on resistors, transistors, and variable potentiometers to regulate motor speed.

Key Components & Their Roles

1. DC Motor – The main component whose speed needs to be controlled.
2. Resistors – Limit current flow to protect components.
3. Potentiometer – Adjusts resistance to vary motor speed.
4. Transistors – Act as electronic switches to regulate power.
5. Diodes – Prevents reverse current flow.
6. Battery (9V or 12V) – Provides power to the circuit.

Working Principle

• The potentiometer adjusts resistance, controlling the voltage supplied to the DC motor.
• The transistor regulates current flow based on the potentiometer setting.
• The diode ensures current flows in the correct direction.
• The motor speed increases or decreases depending on the voltage applied.

Wiring Connections

Component	Connection
Potentiometer	Connected to transistor base
Resistor	Limits current to transistor
Transistor Collector	Connected to motor
Transistor Emitter	Connected to ground
Battery Positive	Connected to motor
Battery Negative	Connected to ground

Advantages of This System

✅ No Microcontroller Required – Simple and cost-effective.
✅ Efficient Speed Control – Adjust motor speed smoothly.
✅ Low Power Consumption – Operates efficiently with minimal energy.
✅ Easy to Build – Uses basic electronic components.